1. Field of the Invention
This invention relates to a process and apparatus for the production of particulate sulfur, having a substantially uniform particle size, from molten sulfur.
2. Background of the Art
Elemental sulfur may be obtained by the Frasch Process wherein air and superheated water, at a temperature above 119.degree. C., is injected into subterranean sulfur deposits to melt the sulfur and force it to the surface. Elemental sulfur may also be obtained in large quantities from hydrogen sulfide contained in petroleum refinery gas streams or well head gas. The elemental sulfur is generally transported to field storage or distribution sites in the molten state. The molten sulfur at the field distributing plant may be pumped onto concrete pads open to the atmosphere or into enclosed storage bins, e.g. slip forms, for storage whereupon the molten sulfur solidifies into large slabs. (The slip form may be continuously raised as the sulfur solidifies; therefore blocks of extensive height may be formed utilizing a form of limited height.) The slabs of sulfur must be mechanically broken up for final distribution to the consumer. This operation is cumbersome and entails much labor and expense, and without extensive grinding, the resulting sulfur, in the form of relatively large chunks, is difficult to handle and utilize.
Molten sulfur may be solidified into small prills by employment of "prilling towers" such as shown in U.S. Pat. No. 3,334,159; however, the installation of such towers at distribution sites is costly and is not normally economically justified. In addition, the sulfur prill, obtained from the conventional prilling operation, is a dense, hard bead. This "conventional" sulfur prill may be compared to the more desirable porous prill obtained by use of the inventions described in U.S. Pat. Nos. 3,637,351, 3,769,378, 3,830,631; 4,133,668; 4,302,237 and 4,326,875.
U.S. Pat. No. 3,830,631 is directed to an apparatus wherein molten sulfur and water streams are discharged from separate conduits into intimate admixture in the atmosphere. The sulfur is solidified into porous particles and the momentum of the combined streams is sufficient to convey the sulfur to a desired location on a storage pad. It is stated that this apparatus is useful in conveying molten sulfur from tanks of a truck or tankcar to a storage site for delivery to consumers. While the process and product of this patent are improvements over the particulate sulfur products, and processes for the preparation thereof, found in the prior art, there are certain improvements thereto that would be desirable. For example, a more uniform particle size would be desirable. Moreover, the area required for the process disclosed in the patent might be too great for installation in certain locations. In fact, since the area required for the patented process is fairly large, the process is generally practiced outdoors, whereby wind conditions and other environmental factors may adversely affect the process. In some instances the process may have to be terminated if the wind velocity carries the particulate sulfur product out of the area devoted to practicing the process of the patent. Furthermore, the apparatus utilized in the process of the patent is not modular; therefore the site must undergo extensive preparation for installing such apparatus. Finally, the capital costs associated with handling molten sulfur in the patented process are extensive.
Therefore, one object of the instant invention is to provide an improved process and apparatus for the production of particulate sulfur, having a uniform particle size.
Another object is to provide an apparatus for the preparation of particulate sulfur, from molten sulfur, which is of such simplicity that it can readily be made available in modular form so that it can be placed on site (with minimal site work), connected to utilities, and operated to unload molten sulfur truck and rail transports.
Another object is to reduce the capital costs associated with preparing particulate sulfur from molten sulfur, by eliminating conventional equipment incidental to handling molten sulfur, e.g. steam boilers, steam traced pipelines, pumps and storage pits.
Another object is to utilize the sensible heat of molten sulfur to supply the required amount of heat to the sulfur handling equipment utilized in the handling of the molten sulfur.
Another object is to provide a molten sulfur lift to unload sulfur from rail and truck transports.
Another object is to provide sulfur and cooling water nozzles designed to provide a highly coherent flow and thereby facilitate even quenching and precise shearing of the molten material whereby the resulting particles have a very uniform size distribution.
Further objects and advantages are to provide improved steps, elements, and arrangements thereof in a process effective in accomplishing the intended purposes.
Other objects and advantages of the instant invention will become apparent from a careful reading of the specification.